Mixing of substances

ABSTRACT

Method and apparatus for the intermixing of substances using a capsule formed by a receptacle with an internal sack and a movable, desirably hollow plunger that acts tangentially against the sack. The receptacle, illustratively of plastic, contains a first substance, such as a powder, and the sack, which is metallized to prevent loss of its contents, contains a second substance, such as a liquid. Illustratively, the liquid is monomer and the powder is a resin constituent. When the two substances are mixed, they produce a composite resin which may be used, for example, for dental fillings. When the plunger, also of plastic, is depressed into the receptacle, it engages and squeezes the sack, expelling its contents into the receptacle, and thereafter sandwiches the sack between the plunger and a sidewall of the receptacle.

nited States Patent y Denholtz [54] MIXING OF SUBSTANCES [72] Inventor:

[73] Assignee: Dental Design Systems, East Orange, NJ.

[22] Filed: Mar. 9, 1970 21] Appl. No.: 17,465

Melvin Denholtz, Livingston, NJ.

[52] US. Cl. ..259/48, 206/47 A, 222/94, 259/D1G. 20 [51] Int. Cl. ..B65d 25/08, 865d 81/32, B01f3/12 |58| Field of Search "259/54, 48, 72, 71, DIG. 20; 206/47 A, 63.5; 215/6; 222/94 [56] References Cited UNITED STATES PATENTS 2,527,992 10/1950 Greenberg ..259/DlG. 20

2,653,611 9/1953 Smith ..206/47 A x 2,721,552 10/1955 Nosik ..206/47 A x 3,156,369 11/1964 Bowes et 8].. ..215/6 3,266,671 8/1966 Gelpey ..222/94 3,344,914 10/1967 Bloom et 8].. ....206/63.5 x 3,454,177 7/1969 Bloom ..206/47 A x Feb. 1, 1972 3,537,577 11/1970 Goupil ..206/47 A Primary ExaminerWalter A. Scheel Assistant ExaminerPhilip R. Coe

Att0rney-George E. Kersey [57] ABSTRACT Method and apparatus for the intermixing of substances using a capsule formed by a receptacle with an internal sack and a movable, desirably hollow plunger that acts tangentially against the sack.

The receptacle, illustratively of plastic, contains a first substance, such as a powder, and the sack, which is metallizcd to prevent loss of its contents, contains a second substance, such as a liquid. lllustratively, the liquid is monomer and the powder is a resin constituent. When the two substances are mixed, they produce a composite resin which may be used, for example, for dental fillings.

When the plunger, also of plastic, is depressed into the receptacle, it engages and squeezes the sack, expelling its contents into the receptacle, and thereafter sandwiches the sack between the plunger and a sidewall of the receptacle.

10 Claims, 11 Drawing Figures PATENIEDFEB 11972 3,638,918 SHEET 10F d lNVENTOR ME V/N DENHOL TZ By a V ATTORNEY msursnrsa 11972 w 3.638.918

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SHEET '& (I? d BACKGROUND OF THE INVENTION This invention relates to the intermixing of substances, and more particularly, to the intermixing of a liquid and a powder to form a composite material that is suitable for filling dental cavities.

The materials used by dentists to fill cavities are of two general types: alloys and composite resins. In both cases the materials are formed by the mixing of separate constituents which can be measured and combined as needed. It is more convenient, however, to have the constituents premeasured in separate regions of a disposable capsule which is acted upon when the constituents are to be mixed.

For that purpose, a number of different types of mixing capsules have been developed. Typically the capsules have chambers or compartments which keep the constituents separated until they are to be brought together. Where an alloy is desired, mixing capsules made of plastics have proved to be advantageous.

Such capsules, however, are unsuitable, for example, for the constituents of composite dental resins. These resins are formed by the mixing of a fluid monomer with a suitable powder. Unfortunately, the fluid exhibits considerable osmotic pressure and is able to penetrate walls and mem branes which are of ordinary plastic. There is also fluid loss by capillary action.

Thus. if the monomeric fluid of a composite resin is placed in one compartment of a plastic-mixing capsule and the powder is placed in another compartment, penetration of the fluid into the compartment with the powder causes a reaction which results in premature and useless formation of the composite resin.

In an attempt to overcome the difficulties caused by fluids in plastic-mixing capsules, attempts have been made to use metallic seals. Such a seal can prevent premature passage of a monomeric liquid into a chamber that contains powder. However, a seal has disadvantages of its own. Typically it is ruptured to force a substance from one chamber into another. The rupturing can form shreds or leave ajagged edge that can interfere with subsequent mixing. Moreover, the typical seal is difficult to rupture, and pockets may form where some of the fluid may remain or where some of the powder may be incompletely mixed.

In addition, a seal which prevents fluid from penetrating into a compartment containing powder does not prevent external escape of the fluid, so that after a long period of storage,

the amount of fluid remaining in the capsule is likely to be nonoptimal and, in some cases, may become insufficient.

Accordingly, it is an object of the invention to facilitate the mixing of substances, particularly those substances which form composite resins used in dentistry. A related object is to facilitate the use of liquid substances which exhibit considerable osmotic pressure.

Another object of the invention is to simplify the procedure required for bringing the constituents of an overall material into contact with each other. A relatedobject is to provide a capsule in which the liquid portion of a composite resin may be brought into contact with a powder by the application of only moderate force.

A further object of the invention is to prevent the parts of a mixing capsule or its constituents from interfering with the. intermixing of substances. A related object is to prevent interference by metallic members. Another related object is to prevent the contamination of a mixture by metallic shreds. Still another object of the invention is to provide a mixing capsule in which the constituents of a composite resin, including a liquid, are held apart without leakage of the liquid until the resin itself is needed, at which time the constituents are brought together in a single chamber.

SUMMARY OF THE INVENTION In accomplishing the foregoing and related objects the invention provides a mixing capsule in which a receptacle containing a first substance receives a plunger that can be depressed to apply tangential pressure to an enclosure, within the receptacle, containing a second substance.

To permit the tangential pressure to be applied, the plunger is inserted into the receptacle spaced from an interior sidewall. The major portion of the enclosure is positioned in the space. The tip end of the plunger within the receptacle is contoured to apply the desired tangential pressure.

When the plunger is depressed into the receptacle, the tangential pressure applied to the enclosure, which is advantageously a hermetically sealed, suspended sack, expells its contents into the receptacle. In addition, as the plunger completes its travel into the receptacle, the enclosure becomes sandwiched and immobilized between the plunger and a sidewall of the receptacle.

In accordance with one aspect of the invention, the tip end of the plunger carries a member for penetrating the enclosure as it is sandwiched. One such member is a blade that slices the enclosure; another is a needle-sharp point.

In accordance with another aspect of the invention, the enclosure is a sack that may have a variety of configurations. One type of sack is a blister that is mounted on a sidewall of the receptacle; another type is of an approximately triangular cross section, still another is tear-shaped. The sack advantageously may have a weakened region, as at an apex of the triangular type of sack or near the base of the tear-shaped type.

In accordance with still another aspect of the invention, the sack can be suspended within the receptacle, by, for example, a stem attached at the insert position of the plunger, either from a cap that spaces the plunger from an interior sidewall of the receptacle or a separate collar that surrounds the cap. Alternatively, the sack can be wedged between the plunger and a sidewall of the receptacle. In the latter event, the plunger desirably has an axial groove for a stem of the sack.

In accordance with yet another aspect of the invention, the base of the receptacle includes a bowl portion which is proportioned to form a unitary interior chamber with the interior of the plunger, with the depleted sack isolated in an outer chamber formed between the exterior of the plunger and a sidewall of the receptacle.

In accordance with a further aspect of the invention the sack is of hermetically sealed metal foil, such as aluminum, to hold the fluid constituent of a composite resin without leakage due to osmotic pressure of capillary action. The metal surfaces of the sack are desirably coated with a plastic film to avoid possible contamination. The remaining parts of the capsule, including the plunger and receptacle, are advantageously molded from plastic material, such as polyethylene or polypropylene.

BRIEF DESCRIPTION OF THE DRAWINGS Other aspects of the invention will become apparent after considering several illustrative embodiments, taken in conjunction with the drawings in which:

FIG. 1A is a perspective view of a mixing capsule in accordance with the invention, with portions broken away to reveal interior constructional details;

FIG. 18 is a partial perspective view showing a plunger and associated constituents separated from a receptacle of the mixing capsule in FIG. 1A;

FIG. 2A is a cross-sectional view of the mixing capsule of FIG. 1A showing the plunger before being depressed into the receptacle against an interior, fluid containing sack;

FIG. 2B is a cross-sectional view showing the capsule of FIG. 2A with its plunger partially depressed to produce tangential pressure against the sack and expel its contents into the receptacle;

FIG. 2C is a cross-sectional view showing the capsule of FIG. 2A with its plunger fully depressed and the sack sandwiched between the plunger and a sidewall of the receptacle;

FIG. 3 is a cross-sectional view of an alternative embodiment of the invention employing a blister storage sack and a knife blade at the bottom edge of the plunger for slicing the sack;

FIGS. 3A through 3C are cross-sectional views of the capsule of FIG. 3 showing various stages in the depression of its plunger to expel the contents of the sack into the receptacle;

FIG. 4 is a cross-sectional view of another embodiment of the invention in which an interior sack is suspended in a receptacle by a collar; and

FIG. 5 is a cross-sectional view of a further embodiment of the invention in which an interior sack is wedged between a plunger an a sidewall ofa receptacle.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS Turning to the drawings, FIG. 1A shows a mixing capsule in accordance with the invention formed by a tubular receptacle 11 containing a substance 12 in a bowl portion 11b; a sack 13 suspended within the receptacle 11 against an interior sidewall 11: and containing a second substance (not visible in FIG. IA); and a movable tubular plunger 14 with a knurled end cap He. The plunger 14 is inserted into the receptacle 11 through a collar 15c ofa hollow cap 15 and is depressed to engage the sack 13 tangentially and expel its contents into the bowl 11b.

The lower portion of the cap 15 is a cylindrical insert between the plunger 14 and the receptacle 11. It accordingly has the effect of spacing the plunger 14 away from the interior sidewall lls of the receptacle 11 over a major portion of the region containing the sack 13.

As will be demonstrated in detail, when the plunger 14 is depressed into the receptacle 11 in the direction indicated by the axial arrows, the tip end 14: engages the sack 13, produces tangential pressures which rupture the sack 13 to expel its contents, and then sandwiches the sack 13 against the interior sidewall 113. After the substance from the sack 13 comes into contact with the substance 12 in the bowl 11b, mixing is accomplished by agitation of the compressed capsule 10 by, for example, a standard vibratory device commonly found in dentists offices. The resulting mix is then accessible in the receptacle 11 by grasping the knurled collar 15c to remove the plunger 14, cap 15 and sack 13 as a unit.

The way in which the sack 13 is illustratively held in position by being suspended within the receptacle 1] from the cap 15 is illustrated in FIG. 1B, which shows the plunger 14 and its associated elements separated from the receptacle 11 before compression has taken place.

To hold the sack 13, the cap 15 has a T-slot 15s that extends upwardly from a lower rim 15r. Correspondingly, the sack 13 has a stem with a T-shaped upper portion 13!. As a result, when the capsule 10 is assembled, the sack l3 hangs against the interior sidewall 11s as indicated in FIG. 1A.

It is to be noted that the tip end 14! of the plunger 14 is rounded to exert the desired squeezing pressure against the sack 13 when the capsule 10 is compressed and no particular orientation ofthe plunger 14 with respect to the receptacle 11 is required.

The receptacle 11, the cap 15 and the plunger 14 are advantageously molded from plastic material, such as polyethylene.

The operation of the capsule 10 of FIGS. 1A and 1B and details of the sack 13 are depicted in FIGS. 2A through 2C. In FIG. 2A the plunger 14 is in its extended position preparatory to operation ofthe capsule 10. The rounded tip end 14! of the plunger extends below the rim l5r of the cup 15 to the vicinity of the stem of the sack 13. The latter illustratively contains a fluid substance 16 within walls 13w forming an approximately triangular cross section, with one leg resting largely against the interior sidewalls 11s of the receptacle 11. The remaining legs of the triangle extend to an apex which projects into the trajectory followed by the plunger 14 as it is depressed.

The walls of the sack 13 at the apex have a weakened region l3r. Elsewhere the walls are relatively thick and below the rim lSr jointly occupy substantially the entire space between the tip end 14! of the plunger and the interior wall 11: of the receptacle.

Constructionally, the sack 13 is of metal foil to prevent loss of the fluid 16 by leakage during storage due to, for example, osmotic pressure or capillary action and desirably has a plastic coating on both interior and exterior surfaces to prevent contamination and facilitate heat-sealing. Once the fluid 16 has been placed in the sack 13, the latter is hermetically sealed and positioned in a desired fashion with respect to the receptacle 11.

Thus the capsule 10 is suitable for use with the new liquids and powderlike constituents that are mixed to form composite materials for dental fillings. The fluid 16 in the sack 13 may be any representative monomer such as methacrylic acid liquid while the substance 12 in the bowl 11b is ofa complementary type which forms a composite resin from the liquid when the two substances l2 and 16 are mixed. A representative powder 12 is an epoxy resin with suitable fillers, such as glass beads and rods, aluminum silicate and tricalcium phosphate. Other suitable complementary substances, including liquids and resin powders, are well known in the art.

As the plunger 14 is depressed into the receptacle 1] through the cap 15, the tip end 141 exerts pressure against the sack 13, which pushes it into the space between the path of the plunger 14 and the interior sidewall 11s. The resulting pressure causes the sack 13 to burst at the weakened apex and eject the fluid 16 into the bowl 11b. The posture of the plunger 14 midway through its travel is pictured in FIG. 2B.

As the cap 14c of the plunger 14 continues to the final position indicated in FIG. 2C, the walls of the sack l3 become completely sandwiched between the plunger 14 and the interior wall 11: of the receptacle and the tip end 14! of the plunger engages a mating surface at the bottom abutment 11a of the receptacle to form a unitary chamber containing both the fluid l6 expelled from the sack l3 and the substance 12. The sack 13 becomes immobilized in a chamber where it is kept from interfering with the subsequent mixing operation.

Since the fluid 16 in the sack 13 is expelled by tangential pressure applied by the plunger 14, the sack 13 is readily ruptured without resort to the appreciable pressure which is required where a metal foil is used to separate compartments with liquid and powder constituents.

Another embodiment of the invention is provided by the capsule 30 of FIG. 3. This capsule employs a receptacle 31 which is similar to the receptacle 11 of the capsule l0 previously described. In place of a sack 13, however, the interior enclosure of the capsule 30 is a blister 33, with a rear wall 33r against an interior sidewall 31: of the receptacle 31, and a front wall 33fwhich projects into the path or trajectory T of the outer diameter of a plunger 34 as it is depressed into the receptacle 31 through a hollow cap 35. The blister 33, which contains a substance 36 for mixing with another substance 32 in the receptacle 31, may be attached to the sidewall 31s in a variety of ways, as by being adhesively cemented or heatsealed.

Where the substance 36 in the blister 33 is a fluid, the material of the walls 33r and 33f is desirably impermeable, such as metal foil which may be suitably coated with an inert plastic layer where contamination is to be avoided. The tip 34! of the plunger 34 is beveled and mounts a blade 34b for slicing into the blister 33 when the plunger 34 is depressed.

The action of the blade 34b and the tip 34! in expelling the contents 36 from the blister 33 is illustrated in FIGS. 3A through 3C. In FIG. 3A, the plunger 34 has been partially depressed through the cup 35 so that the blade 34b is in contact with the upper part of the front wall 33f. In FIG. 3B the plunger 34 has been depressed over approximately one-half of its travel so that the blade 34b has sliced into the blister 33 and the upper parts of its walls are sandwiched by the tip 34t against the sidewall 31s. The slicing and sandwiching produces pressure which expels the fluid 36 into the bowl 31b into contact with the substance 32. Finally,'in FIG. 3C the plunger 34 is fully depressed with its cap 340 resting against the collar 350 of the cup. Similarly the tip 34! rests against an abutment 31a and the walls of the sack are trapped and isolated within a new chamber 310. The'bowl of the receptacle and the hollow interior of the plunger form a unitary chamber for the mixing of the substances 32 and 36.

Another embodiment 40 of the invention is shown in FIG. 4 with its cap 45 modified to accommodate a ring 45r for suspending a sack 43 at its stem 43s. The sack 43 has a weakened bottom region 43r and is subjected to tangential pressure by the tip 44: of the plunger 44 asit moves through the cap 45.

Still another embodiment 50 is set forth in FIG. 5. A plunger 54 has a groove 54g for the stern 53s of a sack 53 which is wedged against a lower contour 55c of a receptacle cap. The tip end 541 of the plunger 54 includes a needle-sharp point 54p that rips into the sack 53 when the plunger is depressed. The expulsion of the contents from the sack 53, which is of triangular cross section is facilitated by the weakened region 53r at the apex projecting beneath the wall of the plunger.

While various aspects of the invention have been set forth by the drawings and the specification, it is to be understood that the foregoing detailed description is for illustration only and that various changes in parts, as well as the substitution of equivalent constituents for those shown and described, may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. A capsule for the mixing of substances comprising an elongated receptacle, open at one end and closed at the other end, said closed end forming a bowl portion containing a first substance to be mixed with a second substance;

a sealed enclosure containing said second substance and positioned within said receptacle against an interior sidewall thereof beyond said bowl portion;

a movable plunger inserted into the open end of said elongated receptacle for applying tangential pressure to said enclosure to cause it to open and expel said second substance into said bowl portion for mixing with said first substance.

2. A mixing capsule as defined in claim 1 wherein said plunger is cylindrical with a contoured tip end and is circumferentially spaced from the interior sidewall of said receptacle and said sealed enclosure is a sack with the major portion thereof positioned within the space between said interior sidewall and the path of movement of said plunger.

3. A mixing capsule as defined in claim 2 wherein said sack is affixed to said interior sidewall.

4. A mixing capsule as defined in claim 2 wherein the tip end of said plunger includes means for penetrating said enclosure.

5. A mixing capsule as defined in claim 4 wherein the penetrating means on the tip end of said plunger comprises a cutting blade.

6. A mixing capsule as defined in claim 2 wherein said sack is elongated.

7. A mixing capsule as defined in claim 6 wherein the elongated sack is suspended in said receptacle.

8. A mixing capsule as defined in claim 2 wherein said plunger has an axial groove in the outer surface thereof and said enclosure comprises a sack with a stem that lies in said groove of said plunger.

9. A mixing capsule as defined in claim 2 wherein said sack is of metal foil with a plastic coating on interior and exterior surfaces to facilitate the sealing thereof.

10. The method of mixing substances comprising the steps 0 l. depressing a plunger of a capsule into a receptacle containing a first substance to apply tangential pressure to an enclosure for a second substance;

2. expelling the contents of said enclosure into said receptacle by said plunger;

3. trapping said enclosure between said receptacle and said plunger; and

4. agitating said capsule to mix said first substance with said second substance. 

2. A mixing capsule as defined in claim 1 wherein said plunger is cylindrical with a contoured tip end and is circumferentially spaced from the interior sidewall of said receptacle and said sealed enclosure is a sack with the major portion thereof positioned within the space between said interior sidewall and the path of movement of said plunger.
 2. expelling the contents of said enclosure into said receptacle by said plunger;
 3. trapping said enclosure between said receptacle and said plunger; and
 3. A mixing capsule as defined in claim 2 wherein said sack is affixed to said interior sidewall.
 4. A mixing capsule as defined in claim 2 wherein the tip end of said plunger includes means for penetrating said enclosure.
 4. agitating said capsule to mix said first substance with said second substance.
 5. A mixing capsule as defined in claim 4 wherein the penetrating means on the tip end of said plunger comprises a cutting blade.
 6. A mixing capsule as defined in claim 2 wherein said sack is elongated.
 7. A mixing capsule as defined in claim 6 wherein the elongated sack is suspended in said receptacle.
 8. A mixing capsule as defined in claim 2 wherein said plunger has an axial groove in the outer surface thereof and said enclosure comprises a sack with a stem that lies in said groove of said plunger.
 9. A mixing capsule as defined in claim 2 wherein said sack is of metal foil with a plastic coating on interior and exterior surfaces to facilitate the sealing thereof.
 10. The method of mixing substances comprising the steps of: 